In a cataract surgery, a phacoemulsification needle is inserted into the capsular bag of a patient's eye through the cornea and the anterior chamber. Ultrasonic energy is supplied to the needle to emulsify the crystal lens of the eye. Emulsified pieces of the crystal lens are aspirated by the needle, and viscoelastic fluid is supplied through the needle into the capsular bag. An intraocular lens (IOL) is inserted into the capsular bag after the crystal lens has been removed by such processing.
In other techniques of eye surgery, a phakic intraocular lens (PIOL) is inserted into the anterior chamber of the eye or into the posterior chamber of the eye, without removing the crystal lens of the eye.
To obtain an optimal result in such surgery, where an intraocular lens is implanted into the anterior chamber, the posterior chamber or the capsular bag, it is important to select an intraocular lens of a size suitable for a patients eye. Lens sizes for anterior chamber phakic intraocular lenses and for posterior chamber phakic intraocular lenses have commonly been estimated by adding 0.5 to 1.0 mm to the horizontal white-to-white corneal diameter. However, the white-to-white corneal diameter is not a reliable indicator for the angle diameter of the anterior chamber and the sulcus diameter, also referred to as sulcus-to-sulcus diameter, of the posterior chamber. In particular, it is difficult to determine the sulcus diameter and the diameter of the capsular bag from outside of the eye since the iris prevents optical measurements of the corresponding tissue portions of the eye.
It is desirable to provide methods and systems suitable for measuring geometries of eye tissues.